Saturday, July 18, 2015

James McCann has excelled at stopping the running game and pitch blocking in 2015(Photo credit: MLive.com)One of the hardest parts of the game to quantify is catcher defense. It is believed by some baseball insiders that handling of pitchers is the most important defensive skill of any catcher. By pitcher handling, I mean studying opposing batters, game calling, understanding pitcher abilities and tendencies, helping pitchers maintain focus and other duties unique to the catching position. These things are difficult to measure because we do not know how much of good pitching is due to the pitcher versus the catcher. Much of pitcher management is still a mystery to statistical analysts, but there are some things than can quantified.

The algorithm I have used to evaluate catchers is complex and will not be described in detail here, but the methodology can be found in an earlier article. I do want to give credit to others such as Sean Smith, Justin Inaz, Matt Klaasen and Mike Rogers who inspired me with similar work in the past. The system evaluates catchers based on what we can most easily measure - controlling the running game, pitch blocking and avoiding errors. Thanks to analysts such as Mike Fast, Max Marchi, Dan Brooks, Jonathan Judge and Harry Pavlidis, a relatively new component - pitch framing or receiving - can also be added to the formula

I'll use Detroit Tigers backstop James McCann as an example. Based on innings caught, stolen bases attempted, runners caught stealing and league caught stealing rate (all found at Baseball-Reference.com), it is estimated that McCann has saved the Tigers about three runs (2.9) compared to an average catcher so far this year. This is third best in the majors.

Similarly, passed ball and wild pitch rates suggest that McCann has saved the Tigers an estimated two runs (1.9) with pitch blocking which is good for fifth in the majors. McCann has saved the Tigers an additional run by avoiding errors - fielding (0.6) and throwing (0.3).

Data for another catching skill - pitch framing - can be found at Baseball Prospectus. The algorithm was developed by researchers Jonathan Judge, Harry Pavlidis and Dan Brooks. They do a good job of introducing this very complex topic here. According to Pitch f/x data, there should have been 1,291 strikes called with McCann behind the plate. There were actually 1,262 strikes, so he cost the Tigers 29 strikes with translates into an estimated two runs (-4.3).

The five elements listed above (stopping the running game, pitch blocking, avoiding throwing errors, avoiding fielding errors and pitch receiving) are combined to arrive at total runs saved. McCann's numbers summed to just over one run (1.4) indicating that he has saved the Tigers an estimated one to two runs overall with his catching. If we omit pitch framing from the equation, McCann saved the Tigers 5.7 runs which is second to Yadier Molina of the Cardinals. So, McCann has been good at stopping the running game, pitch blocking and avoiding errors, but not so good at pitch receiving.

Like other defensive algorithms, this system should be taken with a grain of salt. First, it does not address important pitcher management skills. Moreover, pitch receiving measurement is still new. There is evidence that these numbers tend to stay relatively consistent from year to year though indicating that they probably describe real skills to some extent.

Table 1 below shows that Giants receiver Buster Posey is the MLB leader with 14.2 runs saved in 2015. He has been especially good at pitch receiving (8.7 runs). Jason Castro of the Astros is next with next with 12.4 total runs saved.